Novocaine allergies=> cocaine allergies?

Possibly. Both local anesthetics are esters, which means they are in the same family. However, true allergy is rare. Most commonly it is a side effect of Epinephrine added or a preservative. Lidocaine, Marcaine and other amide local anesthetics shouldn't cross-react. Cocaine has its own side-effects that are very dangerous so stay away, allergic or not.
Not the same. Novacaine is not Cocaine and an allergy to one does not cross over to an allergy of the other.